A-LevelChemistryHalogen derivativesOct/Nov 2016Paper 1 Q221 Mark

The reaction CH₃CH₂CH₂CH₂Br + OH⁻ → CH₃CH₂CH₂CH₂OH + Br⁻ proceeds via an SN2 mechanism. The reaction (CH₃)₃CBr + OH⁻ → (CH₃)₃COH + Br⁻ proceeds via an SN1 mechanism. Which statement about these two reactions is correct?

Q: What topic does this question test?

This question tests Halogen derivatives in A-Level Chemistry (syllabus code 9701). It is worth 1 mark.

ABoth reactions involve homolytic bond fission.

BBoth reactions involve hydroxide ions acting as electron pair donors.

CBoth reactions involve the formation of a positively-charged intermediate.

DBoth reactions occur in a single step.

✓ Correct Answer

The correct answer is B: Both reactions involve hydroxide ions acting as electron pair donors.

📋 Examiner Report & Trap Analysis

Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...

🎯 Mark Scheme Breakdown

Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.

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About This A-Level Chemistry Question

Topic

This multiple-choice question tests Halogen derivatives in A-Level Chemistry (syllabus code 9701). It is worth 1 mark.

Source

This question appeared in the Cambridge A-Level Chemistry Oct/Nov 2016 examination, Paper 1 Variant 2.

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